extends SceneTree

## Does the character actually hold each weapon DIFFERENTLY?
##
##     godot --path . -s res://debug/weapon_hold_check.gd
##
## Every weapon used to be solved as a rifle: stock in the shoulder pocket,
## support hand out along the barrel, muzzle on the aim line. So a knife, an AWP
## and a rocket launcher produced the same pose, and the only thing telling a
## viewer what was being carried was the weapon mesh itself — which at the
## distance an enemy is usually seen is a few pixels.
##
## This asserts the consequence, not the plumbing. Setting `support_mode` and
## reading it back proves nothing; a hold system is easy to build so that the
## profile loads, the enum is stored and the JSON round-trips while the arms do
## not move. So it measures WHERE THE HANDS AND HEAD ACTUALLY ARE, per weapon,
## and requires the poses to be distinguishable from each other.
##
## ── Measured from inside the modifier pass ──────────────────────────────────
##
## Godot restores every bone's local pose after `SkeletonModifier3D` runs, so
## reading `get_bone_global_pose` from a SceneTree script recomputes the globals
## from the ANIMATION alone — the shooter hold is not in what you measure, and
## every weapon would report an identical pose whether or not this feature
## exists. That is the single most expensive trap in this repo; see
## `references/verification.md`. The `PoseProbe` below is the fix.
##
## ── Measured in the SHOULDER's frame ────────────────────────────────────────
##
## Not in world space, and not even in skeleton space. The hold breathes — a
## `sin(_time * 2.2) * 0.012` on the muzzle pitch — and the idle clip moves the
## whole torso, so no hand is ever at the same place twice and two samples of the
## SAME weapon would differ by more than two different weapons do. Taking each
## hand relative to the right shoulder joint, in the chest's own basis, cancels
## both, because they move the shoulder and the hand together.

const LAB := "res://debug/rig_lab.tscn"

## One weapon per style, plus the two rifles, so the table covers every branch
## and also shows that two weapons of the SAME style stay close together.
const CASES := [
	["ak47", WeaponHoldProfiles.RIFLE],
	["m4", WeaponHoldProfiles.RIFLE],
	["mp7", WeaponHoldProfiles.SMG],
	["awp", WeaponHoldProfiles.SNIPER],
	["double_barrel_shotgun", WeaponHoldProfiles.SHOTGUN],
	["rocket_launcher", WeaponHoldProfiles.LAUNCHER],
	["knife", WeaponHoldProfiles.BLADE],
]

## Two weapons of DIFFERENT styles must place their hands at least this far
## apart, in metres, measured in the shoulder frame. Small — these are stylised
## characters with ~0.47 m arms — but far above the millimetre of noise the
## shoulder-frame measurement leaves behind.
const MIN_STYLE_SEPARATION := 0.045
## Two weapons of the SAME style should agree to within this.
const MAX_SAME_STYLE := 0.06

var _fails := 0
var _probe: PoseProbe = null


## Snapshot the pose from INSIDE the modifier pass. See the note above.
class PoseProbe extends SkeletonModifier3D:
	var pose: Array = []

	func _process_modification() -> void:
		var skel := get_skeleton()
		if skel == null:
			return
		pose.resize(skel.get_bone_count())
		for i in skel.get_bone_count():
			pose[i] = skel.get_bone_global_pose(i)


func _init() -> void:
	await process_frame
	var lab: Node = load(LAB).instantiate()
	root.add_child(lab)
	for _i in 200:
		await process_frame

	if lab._model == null or lab._model._pose_mod == null:
		_expect(false, "the lab built a character with a pose layer")
		_done()
		return

	var skel: Skeleton3D = lab._model.skeleton
	_probe = PoseProbe.new()
	skel.add_child(_probe)
	# AFTER the pose layer, so what it reads is what renders.
	skel.move_child(_probe, skel.get_child_count() - 1)

	var samples := {}
	for case in CASES:
		var weapon_id: String = case[0]
		var want_style: String = case[1]

		_expect(WeaponHoldProfiles.style_for(weapon_id) == want_style,
			"%s is held as a %s" % [weapon_id, want_style])

		# Whether this character has a SAVED hold for this weapon, which is
		# allowed to disagree with the style profile. See `_compare`.
		var tuned: bool = not WeaponHoldTuning.resolve(
			WeaponHoldTuning.load_all(), lab._skins[lab._skin].id,
			weapon_id).is_empty()

		lab._model.hold_tune = {}
		lab._model.set_weapon("res://weapons/%s.gd" % weapon_id)
		# Long enough for HOLD_SMOOTH to arrive and for the weapon's `ready` to
		# have measured it. The hold blends in at ~8/s, so ~60 frames is several
		# time constants.
		for _i in 90:
			await process_frame
		samples[weapon_id] = _sample(skel, lab._model)
		if not samples[weapon_id].is_empty():
			samples[weapon_id]["tuned"] = tuned

	_report(samples)
	_compare(samples)
	_done()


## Both hands and the head, relative to the right shoulder, in the chest's basis.
func _sample(skel: Skeleton3D, model) -> Dictionary:
	var mod = model._pose_mod
	var sh_i: int = mod._idx.get("DEF-upper_arm.R", -1)
	var chest_i: int = mod._idx.get("DEF-spine.003", -1)
	if chest_i < 0:
		chest_i = mod._idx.get("DEF-spine.002", -1)
	var hand_r: int = mod._idx.get("DEF-hand.R", -1)
	var hand_l: int = mod._idx.get("DEF-hand.L", -1)
	var head_i: int = mod._idx.get("DEF-head", -1)
	if sh_i < 0 or hand_r < 0 or hand_l < 0:
		return {}

	var pose: Array = _probe.pose
	if pose.size() <= maxi(maxi(sh_i, hand_r), hand_l):
		return {}

	var shoulder: Vector3 = pose[sh_i].origin
	# The chest's rotation, so a torso lean does not read as a moved hand.
	var frame: Basis = Basis.IDENTITY
	if chest_i >= 0 and chest_i < pose.size():
		frame = pose[chest_i].basis.orthonormalized()
	var inv := frame.inverse()

	var out := {
		"r": inv * (pose[hand_r].origin - shoulder),
		"l": inv * (pose[hand_l].origin - shoulder),
		"style": model.hold_style,
		"support": mod.support_mode,
		"hold_l": mod._hold_l,
	}
	if head_i >= 0 and head_i < pose.size():
		# The head's TILT, which is what a cheek weld is. Taken as the angle
		# between the head's up axis and the chest's, signed about forward, so a
		# weld (toward the weapon) and a lean-away come out opposite.
		var head_up: Vector3 = pose[head_i].basis.orthonormalized().y
		var local := inv * head_up
		out["cheek_deg"] = rad_to_deg(atan2(local.x, local.y))
	return out


func _report(samples: Dictionary) -> void:
	print("\n=== HOLD POSE PER WEAPON (metres, in the shoulder's frame) ===")
	for id in samples:
		var s: Dictionary = samples[id]
		if s.is_empty():
			continue
		print("  %-22s %-9s support=%-7s handR=(%.3f %.3f %.3f) handL=(%.3f %.3f %.3f) offhand=%.2f tilt=%+.1f deg"
			% [id, s["style"], s["support"],
				s["r"].x, s["r"].y, s["r"].z, s["l"].x, s["l"].y, s["l"].z,
				s["hold_l"], s.get("cheek_deg", 0.0)])


func _compare(samples: Dictionary) -> void:
	# Every pair of DIFFERENT styles must be distinguishable.
	var ids: Array = samples.keys()
	for i in ids.size():
		for j in range(i + 1, ids.size()):
			var a: Dictionary = samples[ids[i]]
			var b: Dictionary = samples[ids[j]]
			if a.is_empty() or b.is_empty():
				continue
			# The blade releases its off hand to the animation, so comparing its
			# left hand measures the idle clip, not the hold. Its trigger hand
			# and its free offhand weight are what distinguish it.
			var d: float = float(a["r"].distance_to(b["r"]))
			if a["hold_l"] > 0.5 and b["hold_l"] > 0.5:
				d = maxf(d, a["l"].distance_to(b["l"]))

			if a["style"] == b["style"]:
				# ...unless an artist has tuned one of them for THIS character.
				# The profile is only a defaults layer; a saved hold is meant to
				# be able to disagree with it, and aria's hand-tuned AK-47 sits
				# 0.22 m from the untuned M4 for exactly that reason. Asserting
				# they match would be asserting that the rig lab does nothing.
				if a["tuned"] or b["tuned"]:
					print("  --  %s and %s are both %s but %s is hand-tuned (%.3f m apart)"
						% [ids[i], ids[j], a["style"],
							ids[i] if a["tuned"] else ids[j], d])
					continue
				_expect(d <= MAX_SAME_STYLE,
					"%s and %s are both %s and hold alike (%.3f m apart)"
						% [ids[i], ids[j], a["style"], d])
			else:
				_expect(d >= MIN_STYLE_SEPARATION,
					"%s (%s) and %s (%s) are held differently (%.3f m apart)"
						% [ids[i], a["style"], ids[j], b["style"], d])

	# The blade must actually let go of the off arm — that released arm is most
	# of what makes a one-handed weapon read as one-handed.
	if samples.has("knife"):
		_expect(samples["knife"]["hold_l"] < 0.05,
			"the knife releases the off arm to the animation (%.2f)"
				% samples["knife"]["hold_l"])
	for id in ["ak47", "awp", "rocket_launcher"]:
		if samples.has(id):
			_expect(samples[id]["hold_l"] > 0.9,
				"%s keeps both hands on the weapon" % id)

	# The cheek weld, and its inverse on a shouldered tube. These are the two
	# poses that read at the greatest distance, so they get their own assertion
	# rather than relying on the pairwise distance.
	if samples.has("awp") and samples.has("ak47"):
		var d: float = float(samples["awp"].get("cheek_deg", 0.0)) - float(samples["ak47"].get("cheek_deg", 0.0))
		_expect(absf(d) > 1.5,
			"the sniper welds its head to the stock (%+.1f deg vs the rifle)" % d)
	if samples.has("rocket_launcher") and samples.has("ak47"):
		var dl: float = float(samples["rocket_launcher"].get("cheek_deg", 0.0))
		var dr: float = float(samples["ak47"].get("cheek_deg", 0.0))
		var da: float = float(samples["awp"].get("cheek_deg", 0.0))
		_expect((dl - dr) * (da - dr) < 0.0,
			"the launcher leans the head AWAY, opposite the sniper (%+.1f vs %+.1f)"
				% [dl - dr, da - dr])


func _expect(ok: bool, what: String) -> void:
	if ok:
		print("  OK: ", what)
	else:
		print("  FAIL: ", what)
		_fails += 1


func _done() -> void:
	print("\n=== WEAPON HOLD SUMMARY ===")
	print("Failures: %d" % _fails)
	quit(1 if _fails > 0 else 0)